What is the purpose of the impeller in a turbocharger?

• A. Handles air alone, delivers compressed air to the intake ports where the mixing of the fuel with the injectors takes place.
• B. Mixes fuel with air inside the compressor.
• C. Delivers fuel directly to the cylinders.
• D. Cools the intake air before it enters the engine.

Answer: (A)

The main idea here is what the turbocharger’s compressor (impeller) actually does. Its job is to take in ambient air and compress it to a higher pressure, increasing the air density that reaches the engine. It handles air only and then delivers this compressed air to the intake system, where fuel is injected and combusted in the cylinders. The impeller itself does not mix fuel with air, nor does it directly deliver fuel or cool the air. Cooling, if needed, is handled later by an intercooler after compression. So this impeller’s purpose is to compress the air and feed it to the intake for combustion.